Safety overhead door operator



Feb. 2,' 1960 G. P. GESSELL SAFETY OVERHEAD DOOR OPERATOR 2 Sheets-Sheet 1 Filed April 14, 1958 INVENTOR. G m Q2? 66S5// Feb. 2, 1960 e. P. GESSELL SAFETY OVERHEAD DOOR OPERATOR Filed April 14, 1958 2 Sheets-Sheet 2 INVENTOR.

United States Patent SAFETY OVERHEAD DOOR OPERATOR 7 Glenn P. Gessell, Grosse Pointe Shores, Mich.

Application April 14, 1958, Serial No. 728,380 7 11 Claims. Cl. 26859) This invention relates to overhead door operators and, in particular, to shaft-driven sectional overhead door operators.

Hitherto, sectional overhead doors for garages and industrial buildings have usually been raised and lowered by the so-called traveler operator which moves a carriage connected to the upper panel of the door along a generally horizontal trackway located above and rearwardly of the door opening, the door itself being guided by rollers along approximatelyv inverted L-shaped channel tracks mounted at the opposite ends of the door opening and extending rearwardly therefrom. In the shaftdriven type of door operator, the door is raised and lowered directly by cables wound on drums mounted on a cross-shaft or jack-shaft extending across the door opening on a level above the door opening and driven by an electric motor through a reduction gear set. The weight of the door is counterbalanced by a strong and heavy torsion spring encircling the shaft. 7

In such shaft-operated prior overhead doors, if the door in descending meets an obstruction, the motor continues to drive the shaft and cable drums so as to unwind the cables and counterbalancing spring, thereby taking the tension off the counterbalancing spring and permitting the cables to snarl and jump off the drum when the counterbalancing tension is thus released. The occasional and dangerous result of this is that the door, with its weight thus released from counterbalancing, drops like a guillotine with consequent damage to the building or object in its path as well as serious injuryto persons caught beneath it. In such doors, also, the cables successively tighten and slacken as the panels of the door turn the corners between the vertical and horizontal portions of their guide tracks.

The present invention provides a jack-shaft driven door operator equipped with mechanism which automatically compensates for this successive tightening and slackening of the door-lifting cables as the door panels turn such corners by maintaining a constant tension on the door lifting cables suflicient to keep the cables constantly taut during operation. The present invention also provides tensioned means connected to the door for unwinding the cables off the cable drums at substantially the same speed at which they are simultaneously being wound onto the cable drums during raising of the door.

Accordingly, one object of the present invention is to provide a shaft-driven safety overhead door operator with cables wound on and unwound from motor-driven cable drums to raise or lower the hinged-panel overhead door, and at the same time provide means for automatically maintaining tension on the cables so as to keep them constantly taut while the shaft-driving motor is in operation, thereby preventing slackening and snarling or jumping of the cables off the drums, and consequently preventing plummet-like descent of the door, with resulting damage to property and injury to persons.

Another ,object is to provide a shaft-driven safetyoven.

2 head door operator of the foregoing character wherein the tension applied to. the cables is changed automatically to compensate for the successive tightening and slackening of the cables brought applied to the cables is changed automatically to compensate for the successive tightening and slackening of the cables brought about by the differing positions of the hinged door panels as they turn the Figure 1 is a vertical cross-section through an overhead door equipped with the safety overhead door operator of the present invention, taken along the line 1-1 in Figure 2, showing the tensioning mechanism which automatically compensates for the successive slackening and tightening.

of the cables' as the door panels turn the corners in the guide tracks between the vertical and horizontal portions thereof during raising and lowering of the door; 7

Figure 2 is a rear elevation of the overhead door and safety overhead door operator shown in Figure 1, partly in section along the line 22 in Figure :1; t Figure 3 is a vertical cross-section through a-slightly modified overhead door and safety operator, especiallyv adapted for so-called high-lift doors for-ro'orns with exceptionally high ceilings where relatively high lifts of thedoor are required, taken along the line 33 in Figure 4',

Figure 4 is a fragmentary rear elevation of the modification shown in Figure 3, partly in section along the line 44 in Figure 3; and w Figure 5 is a fragmentary horizontal section taken along the line 55 .in Figure 3.

Safety overhead door operator for low-lift doors I Referring to the drawings in detail, Figures 1 and 2 show a safety overhead door operator, generally desig nated 10, for low-lift doors as installed in a building structure 12 having a door opening 14 closed by ahingedpanel overhead door 16 of a low-lift type where the building structure 12 has a relatively low ceiling 18. The

matic in order to avoid'unduly complicating the showing of the invention.

Bolted or otherwisesecured to theunderside of the f upper cross member 28at each end thereof and extend ing rearwardly therefrom is the forward end of 'an angle member 30 to the rearward end portion of whichis's'ecured the upper endof the arcuately-curvedi pOItlOh.32" of a channel guide track, generally designated 34, hav ing a generally vertical but slightly inclined lower por tion 36' extending from the floor 38 to the IOWlIIeIld. of the arcuate portion, 32fand also having an upper or. horizontal portion 40 connected to the upper end'of :the. arcuate portion 32 and extending rearwardly therefrom; The horizontal portion 40of"each of the channel-guide tracks 34, which are thus of app oximately inverted; L;- shaped form, is supported by spaced struts"42 securejd.- to and depending from the ceiling 18, The channel guide tracks 32, as seen in ,FigureZ, are of approxi rnately el- Fatented Feb. 2,196.0

shaped cross-mean. As seen in Figure 2, the channel L sisting of multiplehorizontallyelongated.panels 44 in-- terconnected'by' multiple" horizontally-spaced hinges.

having upper and flo'wer hing'e' brackets 48 and" 50 with laterally outwardly-extended hinge pins 52.-c'arr'ying guide rollers"54engagleable with thefchannel' guide tracks 34 togui'de" and support the panels 4'40f the door 16 as it moves upward or downward. 1 Secured-to thelowermost sequence, assuming that the collars 82 have been propdoorpan'el 44 near thebotto'i'n' edge56 thereof aref two auxiliaryibracke ts' 58having extendedhinge pins 60 carryingdowe'r guide rollers 62. Also secured as at 64 to the lowermost panel 44 near itslower edge portion 56 and onopposite sidesf thereof (Figure 2) are the lower ends of door hoisting cables 66 which extend upward immediately'behind thejdoor frame 22 and around cable drums68 in a clockwise direction (Figure 1),. the upper endsbeing' anchored to their"respective cable drums 68. The'cabledrums 68' arek'eyedor otherwise drivinglv connected to.a cross shaft or jack sh'aff70, the opposlte end portions offwhichare journaled in bearing blocks 72 resting u on and bolted or otherwise secured to the angle members 30. Also rotatably supporting f erse the, inverted L-shaped channel guide tracks 34.

the cross shaft 70 at approximately the midportion thereof is n intermediatesoringanchorage and bearing block 74*(Figure 2) which isbolted or otherwise secured tothe upper side of ,theupper crossv member 28.

Seated as at 76 in the: bearing block 74,'(Figure 2) are the inner ends of weight-counterbalanc'ing torsion springs 78 coiled around the cross shaft 70 andextending outwardly therefrom in oppositely-wound directions, their outerrends being seated as at 80' in anchor collars 82 which in turn are bolted or otherwise secured asat 84 to.thecross shaft 70'. The cross shaft 70'at one end is drivingly connected to a motor-driven, reduction gear set 86 mounted on a shelf or bracket-88 secured .tothe upper horizontal frame member 28. Tension is exerted on each vertical cable 66 by a floating idler pulley 90 carried by a yoke 92 to which is attached the forward end of a tension spring 94', the' rearward end ,orwhich is-anchore'dto a bracket'96 depehdingfrom and bolted orotherwise securedto-the'angle member 30.

Also anchored toeach cable drum 68at a' location spaced :laterally away fronfits respective *lifting cable 66 is the'forward'end of a tensioning cable 981whichin the: lowered position of the" door 16 shownin Figures 1 and 2is'wo'und'in many'turns around the cable drum 68' (Figure 1 the free end being securedR to the rearward' spring anchorage l 8 ofa tension spring 110, the forward spring anchorage 112 of whichis sec'ured to the cable'98 in such a way as to leave a'slack cable port ion 114'rearwardl'y o fithefo rwar'd' cable an'chorage 112,

so as to permit a certain amount ofstretch of the'ispring 110 before the slack cable portion 114-becomes taut.

paired bent levers 118' (Figure2 spacedlaterally apart from one another by tubular spacers 120 surrounding pivottpin's lz'z earrying' g'n'iiierolle'rs 124 running inthe being later-ally extended to c1 also roll in the channel tracks '40. a

'ln the ope'rat-ion of the safety overheadkioor operator 10, let it be assumed that the door 16 is in its lowered position shown in Figures 1 and2, asa result of which the pull of the cables 66 in unwinding from their cable drums 68 has wound up the torsion springs 78 by rotating the collars '82 upon the cross shaft 70 while the opposite ends of the springs 78 are held stationary in their anchorages 76 in the fixed bearing block 74. As a coning cables 66 upon their respective-cable drumsv 68 and t at the same time unwinding the hitherto wound-up weight-counterbalancing torsion spring 78. This lifting.

action transmitted to the cable anchorages 64 in the lowermost door panel 44 causes the door 16 to move upward while its various guide rollers 54,- 62, 124 and 128 trav- While this is occurring, the paired levers118 are be.-

ing movedupward and rearward by their connections at the-pivot.pins 125 to the brackets 126 on the uppermost door panel 44, pivoting around their pivot pins 122 carrying the guide rollers 124., Atthe same time, the

tensioning cables 98 unwind from their respective cable drums 68, tension thereon being maintained by the stretched tension springs 110 connecting the cables 98 up tothe spring anchorages 108.mounted on the forward ends'of theswinging arms 116..

As the door 16 moves upwardand its panels 44seccessively move around the arcuate portions 32 of the guide tracks 34 into the horizontalportions 40 thereof,

V the tension springs 110 automatically compensate for the successive-tightening and slackening of the cables as the door panels 44 turn the corner portions 32 between the vertical. portions 36 and the horizontal portions 40 of the guide tracks 84. This actionby thetension springs 110 also compensates for the lack of uniform movement of the pivot pins 117-ina horizontal plane relatively to the vertical travel of the brackets 58 secured to the lower most panel '44 of the door 16. At the same time, the

tensioned unwinding of the cables 98 from the cable drums 68 prevents slack from developingin the door lifting cables 66-either during the rise or descent of the wardof their rearward anchorages 108 to the arms 116 prevents excessive stretching of the springs .110.

To lower the door 16 and close theopening 14, the V operator reversely energizes the motorized reduction gear set 86to rotate the cross shaft 70 and cable drum 68 in a counterclockwise direction (Figure 1), unwindingthe door'lifting cable 66 while 9 simultaneously winding up thetenSioning cables 98; and further windingup the weight-counterbalancing torsion springs 78. The re mainder'of'the action is the reverse of that described above for opening the door 16.

At no time during the raising or lowering of the door can the operating mechanism of the door operator 1%) get out of control or run away, even if oneorbothofl the counterbalancingsprings78 should. break. .TIhe liftingcables .66 cannot jump off the cable'd'rums 68 and snarl. themselves or permit the door'16 to drop freely, because they and the' ca'bledrums 68 are kept constantly under a controlled tension by the tension cables 98 and their tension springs llfl'ai'ded by? the floating idler pulleys and the respective tension-springs 94: of 1 the-'latten.

Safety overhead door operator for high-lift doors Figures 3, 4 and 5 of the drawings show a safety overhead door operator, generally designated 120, for highlift doors as installed in a building structure 12 having a relatively high ceiling 18 located at a much greater height above the door opening 14 than the corresponding ceiling 18 of Figure 1, the constructions of the building structure 12 otherwise being substantially the same in both instances, hence the same reference numerals are employed for corresponding parts. Such highceilinged building structures are used, for example, in garages equipped with oiling and greasing racks raised by elevators such as hydraulic or pneumatic pistons.

The high lift door 16 is equipped with hinges 46 between their respective panels 44 as in the installation of Figures 1 and 2, but the paired levers 118 carrying the swinging arms 116 have been omitted. Instead, the tensioning cables 98 are led downward almost vertically (Figure 3) around fixed idler pulleys 122 mounted on axles 124 supported by brackets 126 which in turn are mounted on bases 128 secured to the building structure 12 adjacent the vertical door frame members 24. After passing around the idler pulleys 122, the tensioning cables 98 proceed upward through lower spring anchorages 130 secured thereto to moorings 131 on upper spring anchorages 132 which in turn are hooked at 134 onto approximately L-shaped angle brackets 136 secured to the uppermost door panel 44 adjacent its hinges 46. Between the spring anchorages 130 and 132, the tension cables 98 are provided with slack portions 138 within tensioning springs 140, the opposite ends of which are anchored to the upper and lower spring anchorages 130 and 132. The angle brackets 136 (Figure 5) extend outward around the vertical portions 36 of the channel guide tracks 34 so as to avoid interference therewith.

The operation of the high lift door operator 120 is generally similar to that described above in connection with the low lift door operator of Figures 1 and 2, in that forward energization of the motor-driven reduction gear set 86 and consequent rotation of the cross shaft 70 Winds up the lifting cables 66 upon their respective cable drums 68 and at the same time unwinds the tensioning cables 98 from their respective cable drums 68 while the weight counterbalancing springs 78 also unwind. As the door 16 rises, however, the upward travel of the angle brackets 136 secured to the uppermost panel 44 exerts an upward pull on the upper spring anchorage 132 and also on the moorings 131 of the ends of the tensioning cables 98 secured thereto, pulling the free ends of the cables 98 upward and tensioning the springs 140 as the cables 98 travel around the fixed idler pulleys 122. As the door 16 rises to its open position, due to the great height of the ceiling 18, most of the door panels 44 remain adjacent the vertical portions 36 of the channel tracks 34, and the tension springs 140 exert a constant tension on the tension cables 98 and prevent any possibility of the lifting cables 66 from jumping off their respective cable drums 68 or snarling, even though either or both of the counterbalancing torsion springs 78 should break or otherwise become inoperative. The slack portions 138 of the tensioning cables 98 within the tensioning springs 140 between the spring anchorages 130 and 132 permit stretching of the tensioning springs 140 to compensate for the successive tightening and slackening of the cables in raising or lowering the door 16 as the door panels 44 turn the corners 32 between the vertical portions 36 and the horizon-.

tal portions 40 of the guide tracks 34.

What I claim is: 1. A safety overhead door operator for a building structure door opening comprising a guideway disposed on each side of the door opening in guiding engagement with the door, a substantially horizontal shaft adapted to be rotatably mounted above and across the door opening, a plurality of winding drums operably mounted on said shaft in axially-spaced relationship and drivingly connected to said shaft, an elongated flexible force-transmitting element anchored to each of said drums and adapted to be wound thereon in response to rotation of said shaft, each element being liftingly secured to the door, reversible power-driven shaft-rotating mechanism drivingly and rotatingly secured to said shaft, a door weight counterbalancing device secured to said shaft in counterbalancing relationship with the weight of the door, an

elongated flexible tensioning member anchored to each of said drums and responsive to door-lifting rotation of said shaft to unwind from said drums, and means for operably connecting each of said tensioning members to the door.

2. A safety overhead door operator, according to claim 1, wherein a resilient element is interposed between each of said tensioning members and its respective doorconnecting means.

3. A safety overhead door operator, according to claim 2, wherein each of said tensioning members has a slack portion disposed between its connection to its respective resilient element and the connection of said resilient element to the door.

4. A safety overhead door operator, according to claim 1, wherein said connecting means includes an arm connected near one end to the door and near its other end to its respective tensioning element.

5. A safety overhead door operator, according to claim 1, wherein said .connecting means includes a swinging member pivotally connected near one end to each tensioning element and near its other end to the door.

6. A safety overhead door operator, according to claim 5, wherein a guideway follower is movably mounted in each guideway for travel therealong and wherein each swinging member is pivotally connected intermediatev its ends to said follower.

7. A safety overhead door operator, according to claim 1, wherein an auxiliary resilient tensioning device is disposed in transverse slack-take-up relationship with each force-transmitting element.

8. A safety overhead door operator, according to claim 5, wherein the swinging member is pivotally connected to the door near the upper end thereof.

9. 'A safety overhead door operator, according to claim 1, wherein a direction-changing member is rotatably mounted on the building structure adjacent the door opening below the top thereof in direction-changing engagement with each tensioning member.

10. A safety overhead door operator, according to claim 9, wherein the connecting means is mounted on the door above the direction-changing element.

11. A safety overhead door operator, according to claim 10, wherein a resilient element is disposed above the direction-changing element and interposed between each of said tensioning members and its respective doorconnecting means.

References Cited in the file of this patent UNITED STATES PATENTS 

